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Comparison of Fos Expression in Cardiovascular Brainstem Centers Following Air Jet and Restraint Stress
Author(s) -
Jayaratne Sachini,
Dissanayake Hasthi,
Prestipino Louise,
Polson Jaimie
Publication year - 2015
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.29.1_supplement.lb716
Air jet and restraint are common techniques for studying physiological and behavioral responses to unconditioned psychological stress. Although restraint usually evokes a greater cardiovascular response (1), it is not known whether Fos expression in the brainstem correlates with this difference. In the present study, we determined the number of Fos‐positive neurons in different cardiovascular regions of the brainstem in male SD rats following air jet stress (AJ) and restraint stress (RS). The AJ protocol consisted of a series of intermittent puffs of air (~500 kPa) directed at the rat's face for 15 minutes. During RS, the rat was placed in an illuminated perspex tube (i.d. 8 cm) for 30 minutes. Control rats were left undisturbed. After 2 hours, rats were anesthetised and perfused with 4% paraformaldehyde. Fixed brains were sectioned at 40µm and processed for Fos expression using immunohistochemistry. Representative sections throughout the brainstem were imaged and Fos‐positive neurons in key cardiovascular nuclei counted. Both stress tests elicited greater Fos expression within the pons, hypothalamus, medulla and midbrain when compared to controls. Overall, AJ caused a 2.5 fold increases in the number of Fos‐positive cells, while RS caused a 3.2 fold increase. This was primarily due to increased labelling in the lateral PAG following RS (20 fold increase vs 8 fold following AJ). Our results suggest RS causes greater activation of lateral PAG neurons than AJ.